Inverted E-Axle Power Transmission Assembly With Nested Reducer
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Solution Overview
Problem
Existing power transmission assemblies for electric and hybrid vehicles are complex to install, particularly when converting a thermal vehicle into a four-wheel drive or hybrid vehicle, due to the challenging architecture of the rear axle, which requires a specific design and complicates the installation process.
Innovation Solution
A modular power transmission assembly with an inverted electric machine design where the rotor is radially outside the stator, allowing part of the reducer to be housed within an annular cavity, and a coupler to switch between coupled and uncoupled states, enabling easier integration and reduced footprint, thus facilitating the conversion of vehicles into four-wheel drive or hybrid modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional electric machine architecture is used with the stator radially outside the rotor, then the machine structure is traditional and easier to manufacture, but the footprint is larger and torque at low speeds is reduced
Solution Approach 1:
The patent inverts the conventional electric machine architecture by placing the rotor radially outside the stator. This inversion reduces the machine's footprint and increases torque at low rotational speeds, making it more suitable for vehicle applications where space is limited and low-speed torque is critical.
2Volume of moving object
If the reducer is housed within the annular cavity of the inverted electric machine, then the overall assembly footprint is reduced, but the manufacturing complexity increases
Solution Approach 1:
The patent nests the reducer within the annular cavity of the inverted electric machine. The first pinion is completely housed within the cavity, while the ring gear partially penetrates it, creating a compact integrated assembly that reduces overall footprint while maintaining functional separation of components.
Solution Approach 2:
The patent segments the electric machine and reducer into distinct but integrated components. The stator, rotor, first pinion, and ring gear are separate elements that can be manufactured independently and then assembled, balancing manufacturing ease with compact integration.
3Adaptability or versatility
If the power transmission assembly is designed for direct installation in the rear axle, then integration is achieved, but the rear axle requires special design and installation becomes complex
Solution Approach 1:
The patent designs the power transmission assembly as a universal module that can be adapted to different vehicle configurations. The assembly can be installed in various positions (front axle, rear axle, or other locations) and configured for different drive types (two-wheel drive, four-wheel drive, hybrid, or electric), reducing the need for vehicle-specific custom designs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a compact, efficient power transmission assembly that optimizes energy use, reduces installation complexity, and allows for energy savings by enabling the electric machine to assist or brake the thermal engine, while minimizing energy losses outside specific operating modes.
Implementation Method 1
an electric machine comprising a stator fixed relative to the vehicle and a rotor movable in rotation relative to an axis of rotation of said electric machine
Implementation Method 2
a reducer connected to the rotor of the electric machine, said reducer comprising a first pinion connected to the rotor and a ring gear (105b), the first pinion and the ring gear being 45° bevel gears, arranged at 90° to each other
Data Source
Figure 1~2
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AI summary
The invention relates to a power transmission assembly (100) for a four-wheel drive vehicle (1), comprising an electrical machine (102), a reduction gear (105) and a coupler (106) connected to the reduction gear. The electrical machine is an inverted machine in which the rotor is radially outside of the stator with respect to the axis of rotation of said electrical machine.